Locking hinge



Aug. 20, 1957 l. B. RAcHMAN ET AL LOCKING HINGE Filed sept. 23, 1955 22 20 'g'j 30) le l INVENTORS v ls'AvoRE B. RACHMAN -50 8f SIDNEY Boss.

Q TTORlI/E Y United States Patent Oce 2,803,033 Patented Aug. 20, 1957 LOCKING HINGE Isadore B. Rachman and Sidney Bohh, Philadelphia, Pa., assignors to P. B. R. Manufacturing Co., Philadelphia, Pa., a partnership Application September 23, 1955, Serial No. 536,093

Claims. (Cl. 16-144) The present invention relates generally to folding tables :and more particularly to folding tables of the type disclosed in Patents 2,542,394 and 2,643,926.

An object of the present invention is to provide a novel construction for a light-weight table of sheet metal or the like which folds up into a compact unit for ease of carrying and storing, and which, when opened, provides a large top surface made up of a plurality of sections automatically locked in co-planar relationship. l Another object of the present invention is to provide a new and improvedv foldable table having two or more top sections provided with novel self-locking hinges, whereby the top sections can be quickly and easily, yet securely, locked together in open co-planar relationship, and can be easily released for closing.

Other objects and advantages of the present invention are apparent in the following detailed description, `appended claims and accompanying drawings.

Foldable tables constructed of light-weight sheet metal or the like, which open up to give a large top surface and which close to a compact suitcase-like unit for ease of storing and carrying, have enjoyed great popularity because of the many uses to which they can be put. The most common type is that shown in Patents 2,542,394 and 2,643,926 wherein a pair of generally identical rectangular top sections are hingedly connected together at their abutting center transverse edges to enable the top sections to be positioned either in co-planar open relationship or in compact back-to-back closed relationship, with a lon gitudinal dimension half that of the open top. Another common type of folding table employs :a central top section with a drop leaf at each end having half the longitudinal dimension of the central section; the two leaves being foldable underneath the central section, in back-toback relationship therewith so that, again, the longitudinal dimension closed is half that opened.

These top sections are customarily provided with depending anges integrally formed along their side and end edges. The inner end flanges are in juxtaposed position when the top sections are in open co-planar relationship; the flanges serving as a limit stop to prevent relative opening movement of the top sections beyond their coplanar relationship. However, it is desirable to provide locking means to prevent inadvertent closing movement of the top Sections when upward pressure is applied to the underside of the top adjacent the hinge line. In Patent 2,542,394, this is accomplished by sliding locking bars which automatically interlock the top sections in coplanar relationship when the leg members are shifted to open position. In Patent 2,643,926 there is shown a modiiied sliding locking bar mechanism with a push-button release mounted on one of the hinge-elements.

According to the present invention, there has been developed a further simplied and improved mechanism whereby the hinge-elements can be releasably interlocked (in position to hold the top sections in open co-planar relationship) so as to eliminate the need for separate sliding locking members on the top sections to maintain the table against inadvertent collapse from open position.

Generally speaking, the present invention contemplates the provision of locking notches on the free edges of the overlapped portions of the hinge-elements, anda manually operable slidable locking element mounted on the hinge pin and having an inturned free end adapted to be seated within the aligned notches when the hinge is in open position; the inturned free end having a camming edge enabling it to retract momentarily (to allow the hingeelements to come into notch-registration position) and, subsequently automatically to` return to extended locking position; release of the hinge-elements being effected by manual sliding movement of the lockingelement suicient to move the free end beyond the locking notches.

Referring to the accompanying drawings in which like reference characters indicate like parts throughout:

Figure l is a side elevational View of a folding table embodying the present invention, the table being shown in open position with the two centrally-hinged top sections in co-planar edge-toedge relationship.

Figure 2 is an enlarged fragmentary perspective View showing the under side of the two top sections and one of the hinges.

Figure 3 is a further enlarged fragmentary' side elevational View of the embodiment of Fig. l, showing the top sections and one of the hinges.

Figure 4 is an exploded perspective view of the hinge of Figs. 1-3.

Figure 5 is a cross-sectional view taken generally along the iine 5 5 of Fig. 3.-

' Figure 6 is a view generally like that of Fig. 5 but show ing the cam-actuated retracted position of the locking element.

According to the embodiment of Figs. l-6, the folding table of the present invention has a top formed by a pair of identical sections 20. Each of the top sections 20 is formed' ofl light-weight sheet-metal or the like and is gen-1 erally rectangular in configuration with an integrally formed depending flange 22 having an inturned free edge 24. The top sections 20 are connected in endto-end coplanar relationship by a pair of identical hinges 26.

Each hinge 26 is made up of a pair of hinge-elements 28 and 30. The hinge-element 28 includes a generally vertical portion 32 which is secured to the outside of the side flange 22 by a pair of rivets 34 or the like. The hinge-element 2S also includes an integrally formed portion 36 which extends horizontally and centrally inward from thelower edge of the vertical portion 32 so as to underlie the inturned free edge 2410i the side flange 22 and also the inturned free edge 24 of the central'end flange 22, to which it is secured by a pair of rivets 38, as best shown in Fig-2. A locking notch 40 is formed in the upper edge of the vertical portion 32, slightly inward of the centralmost vertical free edge 42 thereof. A pivot hole 44 is formed in a bottom extension 46 of the vertical portion 32, generally in vertical alignment with the locking notch 40, as best shown in Fig. 4.

The hinge element 3d generally resembles the element- 28 described above except as hereinbelow pointed out. Thus, the element 30 also has a vertical portion 32 secured to the flange 22 by rivets 34 and a horizontal portion 36 secured to the inturned flange edge 24 by rivets 38. However, the centralmost portion of the vertical portion 32 of the hinge element 30 is displaced slightly outwardly so that, when the hinge is assembled, it is disposed in over. lapping juxtaposition to the corresponding centralmost portion of the hinge element 28, as best shown in Figs. 4 and 5.

The hinge element 30 is provided with an uppermost lockingnotchA 40 and a pivot hole 44 formed in a bottom extension 46, as in the case of the hinge element 28. Additionally, the hinge element 30 is provided with a guide boss 48 disposed vertically intermediate the notch 40 and pivot hole 44.

The hinge elements 28 and 30 are pvotally interconnected by a hinge pin 50, which has a head 52, a cylindrical shoulder 54 and a reduced diameter stem 56. The free end of the stern 56 is hollow so that, after it has been inserted into the aligned holes 44, it can be flattened rivetwise to lock the hinge elements together as best shown at 58 in Fig. 5.

A locking slide 6i) is mounted on the outside of the hinge element 30 and, as will be described, functions releasably to lock the hinge elements 28 and 30 together in open position, that is the position shown in Figs. l and 3, wherein the two top sections are in end-to-end coplanar relationship.

The locking slide 60 is formed from a length of thin at steel or other somewhat resilient material and has integrally formed generally horizontal outwardly directed handle 62 at its lower end. Somewhat above the handle 62, the main vertical portion of the slide 60 is provided with an elongated slot 64, through which the hinge pin stem 56 extends. A second elongated slot 66 is formed in the slide 60 above the slot 64; the slot 66 fitting over the guide boss 48. It can be seen that the slide is held against the hinge element 30, by the hinge pin shoulder 54, but is free to move up and down relative to the element 30.

An integrally formed inwardly directed generally horizontal locking tongue 68 is provided at the upper end of the slide 60; the tongue 68 having a vertical camming edge '70 which is inclined inwardly and away from the centralmost vertical free edge 42 of the hinge element 30, as best shown in Figs. 4 and 5.

At the upper end of the guide slot 66, the slide 60 is provided with an outwardly directed lug 72 having a hole 74, within which is anchored the upper end of a coil spring 76. The lower end of the spring 76 is wrapped around the hinge pin shoulder 54 as best shown in Figs. 4 and 5.

The spring 76 normally urges the slide 60 to the lowermost position, shown in Fig. 3 and also shown in solid lines in Fig. 5, wherein the locking tongue 68 extends within the aligned notches di) in the hinge elements 28 and 30, so as to lock the hinge in the open position shown in Figs. l and 3. However, manual upward pressure upon the handle 62 will move the slide, against the pull of the spring, to the uppermost position shown in interrupted lines in Fig` 5. In this uppermost position, the locking tongue 68 has been moved above and clear of the notches 40, thereby freeing the hinge elements 28 and and enabling them to swing (in the direction of the arrows in Fig. 3) about the hinge pin 50 to closed position wherein the top sections 20 are in juxtaposed backvto-back position, as shown in Patent 2,643,926, for compactness in storing and carrying.

As shown in Fig. l, each of the top sections 20 is provided with a pivotally mounted leg member 78 (which may be of U-shaped configuration); the upper ends of the leg members being provided with pivotally connected bracing links 80. The leg members are constructed and arranged to fold hat against the underside of the top sections so that they are enclosed and concealed when the table is closed, as shown in Patent 2,643,926.

As the hinge elements 28 and 3i) swing in the direction of the arrows in Fig. 3, the slide 60 moves with the hinge element 3i). When the handle 62 is released, the spring 76 pulls the slide back to its lowermost position wherein the tongue 68 is disposed within the notch 49 only of the single hinge element 3i).

When the top sections and hinge elements are swung back to open position (that is, in a direction opposite to the arrows in Fig. 3), the inner end of the tongue 68 must be moved out of the way of the vertical free edge of the other hinge section or element 28. This Can optionally be done by manually raising the slide 60 to the elevated position shown in interrupted lines in Fig. 5, and then releasing the slide when the two notches 40 have come into registration, thereby permitting the spring 76 to pull the slide back down to the locking position shown in solid lines in Fig. 5, wherein the tongue extends into both notches and locks the hinge elements together, in the manner described hereinabove.

However, the camming edge 70 makes it possible to dispense with the manual raising of the slide during opening movement of the hinge elements. Thus, during this opening movement of the hinge elements 28 and 30, the inclined camming edge 70 (which protrudes inward beyond the notch of the hinge element 30) is contacted by the centralmost vertical free edge 42 of the other hinge element 28. Further relative pivotal movement of the hinge elements causes the free edge of the element 28 to exert a camming action on the inclined edge 70 and forces the tongue (and the upper end of the slide 60) laterally outward to the position shown in Fig. 6. In this position, the tongue no longer protrudes inward beyond the notch 40 in the element 3i), so that the element 28 is free to move beyond the tongue to full open position, wherein the notches 40 are in registration and the free edge 42 of the hinge element 30 seats against the embossed stop shoulder 82 formed on the vertical portion 32 of the hinge element 28, as shown in Fig. 3.

As shown in Fig. 6, the slide bends somewhat during the camming retraction of the tongue 68. As soon as the two notches iii come into registration, the resilience of the slide 60 returns it to the solid line position of Fig. 5, wherein the tongue enters the two notches 40 and locks the hinge elements 28 and 30 together.

Once the tongue 68 seats within the two aligned notches 40, whether by spring-actuated axial movement (following manual raising of the slide 60) or by inward movement (following cam-actuated bending of the resilient slide), the hinge elements 28 and 30 are securely locked together in open position and can be released by manual upward movement of the slide 60 to the interrupted line position of Fig. 5, as described above.

lt is pointed out that the relatively small locking slide 60 is not called upon to withstand any stress when the table is in use. Thus, it is obvious that the stress generated by any load carried by the open table top sections is in the opposite direction (that is, in a direction opposite to the arrows in Fig. 3) and tends to rotate the hinge elements toward open position. This stress is taken up by the abutting central end anges 22 as well as by the stop shoulder 82. It is only when the table is being closed or opened that 'the locking slide is required to counteract a tendency toward inadvertent closing movement of the hinge elements. This occurs because it is more convenient to open or close the leg members 78 with the top sections in upside-down position as shown in Fig. 2. During the act of turning the table from rightsideup to upside-down position, or vice versa, there would be a tendency for the top sections to swing toward closed position if it were not for the novel locking mechanism of this invention. Without the locking mechanism, it would be extremely awkward and difficult to turn the table over, especially where the top sections are of relatively large size.

The novel locking mechanism of this invention represents the simplest and least expensive way to lock the top sections in open position while the table is being turned over.

The present invention may be embodied in other specific forms and, therefore, the above described embodiment is to be considered in all respects as illustrative and not restrictive, reference being made to the appended claims` as indicating the scope of this invention.

Having thus described our invention, we claim as new and desire to protect by Letters Patent the following:

l. A hinge comprising a pair of hinge elements, a hinge pin extending through and pivotally interconnecting the elements somewhat inwardly of their free edges so as to provide overlapped side-by-side end portions, each of said overlapped end portions having a locking notch spaced slightly inwardly from the free edge of the hinge element, said notches being in overlapping registration when the hinge elements are disposed in generally end-to-end open position, and a locking slide mounted on the hinge pin and keyed to one of the hinge elements for linear movement along the axis of the notch in that element, said slide having a locking tongue extending in a direction generally parallel to the pivot pin and into the aligned notches when the slide is in its normally retracted position and when the hinge elements are in generally end-toend open position, the tongue thereby interlocking the hinge elements against pivotal movement to a closed position, and a spring connected at the ends thereof to the pivot pin and the slide urging the slide toward a retracted notch-engaging locking position, linear movement of the slide against the spring force to extended position causing the tongue to clear the notches thereby freeing the hinge elements for pivotal movement to closed position.

2. A construction according to claim 1 wherein the slide is provided with a handle for manually shifting the slide to the extended unlocking position.

3. A construction according to claim 1 wherein the slide is provided with a longitudinal guide slot, the slot fitting over a guide boss formed in the adjacent hinge element, the boss and slot serving as keying means to permit only the desired linear movement of the slide.

4. A construction according to claim 1 wherein the slide is somewhat resilient and wherein the locking tongue is provided with a camming edge set at an angle to the free edge of the hinge element relatively movable thereto whereby when said hinge elements are pivoted from closed position toward open position said camming edge on the locking tongue is contacted by the'edge of the relatively moving hinge element and forced to move from its normal position in a direction generally parallel to said pivot pin, the slide bending resiliently permitting the hinge edge to clear the tongue, and thereafter causing the slide to snap back into its normal position when the notches come into registration whereby the tongue extends into the notches'locking the hinge in end-to-end open position.

5. A construction according to claim 4 wherein the slide is provided with a longitudinal guide slot, the slot tting over a guide boss formed in the adjacent hinge element, the boss and slot serving as keying means to permit only the desired linear movement of the slide and wherein handle means are provided for manually shifting the slide to the extended unlocking position.

References Cited in the le of this patent UNITED STATES PATENTS Great Britain July 17, 

